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Prinzipien der Herstellung und Stabilität von Emulsionen
Author(s) -
Schubert Helmar,
Armbruster Harald
Publication year - 1989
Publication title -
chemie ingenieur technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 36
eISSN - 1522-2640
pISSN - 0009-286X
DOI - 10.1002/cite.330610906
Subject(s) - laminar flow , emulsion , chemistry , turbulence , population , thermodynamics , chemical engineering , physics , organic chemistry , demography , sociology , engineering
Principles of formation and stability of emulsions. The present state of knowledge concerning the principles of emulsion formation and stability are summarised and new theoretical and experimental results are presented. Also described are the characteristic features of the most common types of machines used for emulsification and the mechanics of droplet disruption in laminar and turbulent flow as well as cavitation. In laminar flow, the minimum droplet size is theoretically determined by the shear stress and regulated by a critical Weber number, provided that the particular emulsifier can rapidly occupy sites on the newly formed interface. If this occupation is inhibited, than only larger droplets can be formed. The upper size limit can be calculated from kinetic considerations. The second part of the paper addresses the fundamentals of emulsion stability and the emulsifier's influence on interactions between dispersed droplets. A way of describing the state of the droplets in an emulsion at rest using a population balance theory is also discussed.